Hello, my location is southern sweden, more specificly next to malmö. I am looking to buy hardware for my pc but I am not sure about what my motherboard can handle. So I will post my systems specification as good as possible. Everything about the moddle is original. The budget is 4000kr, that being about 400euro.
Im looking to upgrade my computers performance so it's to handle the newest games with ease.
The modell is Aspire M5201 and as stated everythings original. It's running on Windows Vista Home premium 6.0.6001 Service Pack build 6001.
Processor : AMD Phenom(tm) 9550 Quad-Core Processor, 220Mhz. Your Phenom 9550 uses an AM2+ socket, which is compatible with AM3 processors.
(http://www.teamliquid.net/forum/viewmessage.php?topic_id=223583) This person installed a Phenom II X4 965 into the same computer as yours with the latest BIOS, so there shouldn't be a problem.

Here are some Phenom II X4 CPUs: http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&DEPA=0&Order=BESTMATCH&N=100006676&isNodeId=1&Description=phenom+II+X4&x=0&y=0 the cheapest one, the 960T, is 826 Kronor(through google currency conversion; I have heard that Sweden has one of the largest taxes in the world in terms of buying online from other countries...)
The Phenom II X4 965 has the best price/performance ratio now: http://cpubenchmark.net/cpu.php?cpu=AMD+Phenom+II+X4+965

Along with UPGRADING the CPU, upgrading to a better Graphics card is also important as many modern games are heavily GPU-dependent. Your motherboard has a PCI-E 2.0 x16 slot. That is good. (http://support.acer.com/acerpanam/desktop/0000/Acer/AspireM5201/AspireM5201sp2.shtml)
I would suggest upgrading to a Radeon HD 6850: http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&DEPA=0&Order=BESTMATCH&N=100006676&isNodeId=1&Description=HD+6850&x=0&y=0 Cheapest one is 926 Kronor, made by HIS.

http://videocardbenchmark.net/gpu.php?gpu=Radeon+HD+6850
Its still in the top 20, so it will provide a good measure of future proofing, and has the best price/performance ratio as of now.

You will need to upgrade your power supply too; AMD recommends at least 500W, so lets get a 600W one in case you plan to upgrade again in the future.
http://www.newegg.com/Product/Product.aspx?Item=N82E16817139028 
CORSAIR Builder Series CX600 V2 600W Power supply. 463 Kronor.

463+826+926=2215 Kronor.

If you want to upgrade further...

You can upgrade to a CrossFire-enabled motherboard which will ALLOW you to run 2 graphics cards on one system.
http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&DEPA=0&Order=BESTMATCH&N=100006664&isNodeId=1&Description=990fx+motherboard&x=0&y=0
990FX motherboards are the top of the line for AM3 systems.
The cheapest one is 860 Kronor, made by ASRock.

So we will get another 6850 to add into your system, which is 926.

860+926+926+826+463 = 4001 Kronor.  That was some really great help. Thanks alot! I'll definetly buy it in the next days. But I will hold back on the extras incase the taxes should get me over the limit on the budget.
Again that was some really brilliant bro tips. You are good and you should feel good  !Okay so turns out I cant order from newegg SINCE they dont do international shipments.. I just checked http://www.tigerdirect.com and they do ship to Sweden.Though I cant find any of  the hardware availible to actually purshase that you recommended me Why don't you just order from a local store? If you have to pay SHIPPING tax, it could be huge on hardware... Just got back from the store. They'll have a set ready within the budget to upgrade my pc in a few days, also I bought a razor mouse, a ps3, a headset and a new tv :333What are the specs of the upgrade? Have fun with your new PS3 Decided to just go with the graphic card, cam, a coupple of ps3 games and weed n' munchies of c