Cpu help

Check to be sure the fan turns on the heatsink. You may also not have the heatsink installed flush. A pin or hold down mechanism may be loose. What heatsink are you using?

im useing a artic cooler have refitted 3 times maybe its a bad chip got 2nd hand ive now put my old dual core back in and its fine maybe the board cant take this chip someone said the bios might need updateing or flashing might be a dead chip but just can understand why it locks up after half hr it might be ok for 10 mins then ill plug in a usb like a mouse or keyboard the locks up driveing me mad but just dont no if i need a new chip or board

Acer systems use low end power supplies. It may be overheating. Nearly all atx power supplies will fit the acer case. The q8200 needs more juice, and the acer power supply may be stressed out. I suggest a new 400-500w name branded ps, such as antec, corsair, ocz, enermax, seasonic, or xfx. Avoid low end brands such as powmax or any lightweight units less than 3 lbs.

Also do a check that the board fully supports the new cpu, it may require a bios firmware update to handle the cpu properly.
Is this the board ?
http://www.specsbox.com/142/msi-n1996-motherboard-specs...
Did you check first to see if the board can support the cpu becuse it look like the answer is no. Or you have the board number wrong.

hi maybe im wrong the pc is a acer M1640 ive just put a 750 watt psu in still the same

http://www.google.co.uk/imgres?q=m1640+motherboard&hl=e...

You didn't mention the new ps, so you should be fine. Here's your board: http://www.ebay.com/itm/Acer-MBSAK09007-AM1640-M1640-So.... You may have to change boards to run your 8200 stable. Acer normally doesn't provide bios updates to run newer cpus. If you have an oem version of windows 7, then this board should fit your case, but you'll have to do a format and fresh install of windows: http://www.amazon.com/Intel-Core-Quad-Motherboard-BLKDG.... This is a bulk oem motherboard and may not include the backplate. Boards with 2 ram slots start at $50 retail with accessories.