I am answers for Monitor /PC mobo dead. only ,not windoz ever, and Linux works best here. fact.I see you lost the beeper device (SOLVED ) !!!Not putting in a new RTC CMOS COIN cell battery first, is bad. ($1 fix)A bad coin cell make BIOS Dead or BIOS tells all lies endlessly. the cure is $1well no history told at all , 11 years old and coin cell dead. I bet.bought a bad 11 year PC that or just failed 11 years in use, bought it dead, or failed just out of the blue, not TOLDno history of PC told. at all. the mobo some versions of 7, beep and others flash led codes.dead PC , monitor tests good.(evidence)no signal means video port dead or set to the wrong port on the monitor,do not trust auto mode set it manually in OSD. okis this a VGA cable , no bent pins?Does the PC have PCIe video card , if yes remove it and use the case mounted vga port blue on mobo rear edge. Dead signs on relic VISTA PC.2007MOBO.FIRST OFF BIOS DOES NOT MAKE SOUNDS TO ANY SPEAKER PORTS. EVER. (WINDOWS DOES)YES THE POST BIOS BEEPER CAN MAKE BEEPS ON ANY AND ALL P.0.S.T ERRORS. NO PHOTOS YOU PC AT ALL, REAR NOR INSIDE WITH LEFT LID OFF,(so they helper is blind.next you never said the monitor is VGA, sorry we can not guess that.Not told at all if monitor was connected to the chassis (vga port or the VGA video car.sno fans.????? (pcu FAN DEAD, ,CPU FAN DEAD, OR CASE FANS DEAD, AND IF GPU CAD, GPU FAN DEA.NO CLUES THERE TOLD AT ALL AND CPU/PSU FAN MUST NOT BE DEAD. forget EXT speakers, unplug that. until , monitor works now and windows runs, (or linux, etc)no beeps, hdd heard (ear) no bioSTAR splash screen means pre POST is Dead and bios is dead. and VGA port is dead.bad PSU or PSU overloaded it seems to based on limited evidence.no lights so that means power button led is deada new coin cell battery is first bios hot key is? num-lock key OFF !!!!!F2/ DEL:? is reset bios to defaults (im reading your manual to you NOW) if you can get a splash screen . and post to finish.the monitor must be good and no-signal tells me that texted to screen. so monitor is good.the most sad part of all no photos posted of rear of mean, So I can see things connected wrong (sad :(The VGA port is dead and PSU is dead too.why is the question CPU socket has bent pins, seen used mobo on ebay lots. Core 2 Quad / Core 2 Duo / Pentium D / Celeron1:coin cell dead. sure it is. (next to CPU)in a vertical socket,.2: PSU not bad (caps inside a wreck, bad) 4 pin and 24pin DC power plug to mobo , now.3: PSU overloaded, strip down the PC. to find what is shorted4 : MOBO jumpers missing or inserted INCORRECTLY per the MOBO manual , words. JCMOS1?DO not flash bios on any sick PC or you brick it, (oops buy it dead like this OOPS)testing firstmonitor VGA cable to VGA port rear of mobo, mounted to MOBO called the onboard VGA port.no PCI cards NOWno usb devices (keyboard added if BIOS wakes up) use rear USB for keyboard only (for now)no hdd or dvd drives connected. not yet.1 stick of DDR ram tested 1 by 1.no video cards. now. (just to be clear I repeat this ok/)If the PSU is not bad , now, and monitor still dead, the MOBO is badPSU 24 pin and 4 pin power must be connected to the mobo now. the 4 pin us just above the VGA jack,if all is still dead. unplug the PC (PSU) from wall AC power overnight or moreIN the morning or later try again. (PCs can in fact latch up, and this AC power trick , can wake it upand now the BIOS SPLASH screen shows and F2 BIOS hot key and all BIOS pages work,, now.Warning , never hot plug any parts inside the PC with AC cord connected to AC WALL power.that is called Hot swapping will blow parts up, for sure DDR. memory for sure power DC cables hot swapped (boom)do not do that and not wreck good electronicsHint1, the keyboard LED dead mens lost of 5vdc , from the PSU., (USB ) if using USB keyboard , not told that. P/S2?Hint2: some version of these mobo (many) have no onboard BEEPer device (sonic) not sure how it does POST errors, but the book says,(free) some have beeper device and the manual shows AMI beep codes page 25v6.5 is not easy to find docs. also some BIOS here use he DEL key (not F2) to gain BIOS pages. at power on. (keyboard USB only)the caps lock key must not be set wrong or DEL key will be dead (DEL/dot) dot mode fails on some.https://www.manualslib.com/manual/391164/Biostar-G31-M7-Te-Bios.html?page=3&term=key&selected=2#manual andhttps://www.manualslib.com/manual/391165/Biostar-G31-M7-Te.html?page=27&term=beep&selected=1#manualthis PC was built in The Cap plague year 2007, so was PSU? and they all leaked acid or bulged.to bench test a PSU ask, (using just a paper clip unbent) ASKoddities, on this mobo, wow, losts but this one takes the cakeJUSBV1: Power Source Header for USB Ports