my gigabyte system runs only fans, no boot, not leds, no bios nothing!

[atstech]

@MODS
I have the following below mentioned system, which was working fine until 2 days back, when i used a SWITCHED OFF system to charge my friends phone's, about 5 of them and then later the next day i tried to switch on my pc! and ALAS only fans work!

my System config;
GA-990XA-UD3 MB
AMD FX-8120   PROCESSOR
CORSAIR VENGENANCE  RAM
GIAGBYTE CASING AND
800W PSU GIGABYTE AGAIN
AND A BASIC VIDEO CARD!

I NEED TO know, do i need to completely disassemble and start assemling from the scratch or is there some particular areas to trouble shoot!
wbr
atstech.

[AgentFXA]

Check psu voltages first - the phones' recharge possibly killed a voltage hence no more bootup.

If psu voltages are all fine then your mobo got hit.

[Noz]

I had a kinda similar problem, my pc was working fine, but I decided to clean it a bit and dust it of so I disassembled everything, dusted it of with a paint brush, reassembled it and switched on the pc then a black screen, but the fans  are working.
So I manually cleared my bios by putting a screwdriver on the cmos pannels,the pc rebooted on the bios screen, I then applied all default setting and rebooted then the pc worked again.
All of a sudden it rebooted and a black screen and only fans working. I tried to clear cmos again but it does not work at all, I've tried a very thing removed everything, placed back in but nothing works only the fans.
System:
Gigabyte ga-b75m-d3h
6 gigs ram
450 what power sypply
1 terabyte
I5 cpu

[atstech]

I had a kinda similar problem, my pc was working fine, but I decided to clean it a bit and dust it of so I disassembled everything, dusted it of with a paint brush, reassembled it and switched on the pc then a black screen, but the fans  are working.
So I manually cleared my bios by putting a screwdriver on the cmos pannels,the pc rebooted on the bios screen, I then applied all default setting and rebooted then the pc worked again.
All of a sudden it rebooted and a black screen and only fans working. I tried to clear cmos again but it does not work at all, I've tried a very thing removed everything, placed back in but nothing works only the fans.
System:
Gigabyte ga-b75m-d3h
6 gigs ram
450 what power sypply
1 terabyte
I5 cpu

Check psu voltages first - the phones' recharge possibly killed a voltage hence no more bootup.

If psu voltages are all fine then your mobo got hit.

thanks guys for your replies! ill change the PSU and see if my pc boots!
WBR
Atstech.