Ok so im completley new to gaming on pc's I don't want to make the best gaming rig, I've come across a pc that i want to maximise by adding parts, on a budget

i've obtained a pc for £60 of my brother

AMD phenom 9650 qaud
4gb DDR2 RAM - I want to improve (if in your opinion it needs to)
640GB HDD (do not care to change)
nVidia GeForce G100 512 mb ram - I want to improve

I'm not looking to play the best looking games, but I would like to play games like portal and on a budget, I don't want to spend more than £150 adding parts

I love buying older parts and then maxing them out...

I'll list what I would do, you can choose what to upgrade.

1. I'd find out if the mobo is AM2 or AM2+ and if it supports 125W CPUs. If it does I'd pick up a Phenom II X4 965. they are like 90 bucks and very good bang for the buck. I'd also invest in a aftermarket CPU cooler if getting a new CPU and overclock to 4Ghz.

2. I'd see how many RAM slots I have. 4GB is ok actually but if you have 2 free slots, you can grab another 4 GB no problem. It's not easy finding 4GB DDR2 RAM in a single stick (for a good price). If you're upgrading the RAM, try to get the same speed as the one you currently have.

3. SSD as a boot drive and a fresh install of windows is a must. No questions about it.

4. If you keep your system as is I'd pick up a Radeon 7770 or 7850 1 GB. Anything higher and you will bottleneck the card with your computer. If you upgrade to Phenom 965, 8 GB of RAM, you can get a 7870, GTX 660 etc...

http://www.ebay.co.uk/itm/Sapphire-Technology-AMD-Radeon-7770-HD-1GB-Graphics-Card-PCI-Express-3-0-HDMI-/360591656144?pt=UK_Computing_Computer_Components_Graphics_Video_TV_Cards_TW&hash=item53f4f004d0

Thats the radeon 7770 i think, dam i hate being in the Uk, thats about $128 roughly (£85)

so i might go with that, if i added the AMD Phenom 2 x4   3.4ghz thats another £80 

Thats roughly about budget, what sort of games couldn't i play on that set up?

Pretty much everything will be playable and run fairly smooth. You will have a choice of 1080p and medium/high details but no Anti Aliasing. Or 720p and all high with 2-4X Anti aliasing. GPU will be the main bottleneck as the Phenom 965 is a fairly capable CPU.

Make sure your mobo supports that CPU thought. Usually manufacturers have lists of which CPUs are supported on their site.

Also, getting a 60 GB solid state drive as your boot drive and isntalling windows on it will speed up your machine much more than any of these other upgrades will. I literally cant go back to using a mechanical drive anymore. Too much loading...