my programs keep closing.

Okay so my laptop is an Acer aspire 3662WLMi. I bought it off ebay and yesterday resetted the whole operating system and changed it to windows XP professional instead of XP home. All the games i have keep automatically closing. Sometimes it lets me play for 5 minutes but neatly all the time i doesn't even let me get to the first level. This is with EVERY game i have(games like diner dash, and other dash games, etc) so they aren't big games at all. I've tested them on my boyfriend's laptop and they work fine, his computer is vista and these games play perfectly and yes, when i download them it says it can be played on XP too. Here's the details of my computer:

System:
Microsoft Windows XP
Professional
Version 2002
Service pack 3

Computer:
Intel(R) Celeron(R) M CPU
420 @ 1.60 GHz
1.60 GHz, 1.87 GB of RAM

I also have Avast anti-virus and Malwarebytes anti-malware(and malwarebytes keep saying Error(722,09) every time i do scan.) There's no virus on my computer as i know so i have no idea why my games and internet explorer keep closing.

Dad said i have shared memory, so i don't know if i have a good built in video card/grahics card or if i even have them at all! oh and sometimes my internet explorer shuts down by itself, its taken me 10 minutes just to get to this webpage home!

I thought by completely deleting the system and starting from scratch would fix it but it didnt. I thought it was maybe something to do with Service pack 3, because i used to have a DELL laptop service pack 2 and these same games worked 100% but dad keeps saying its not that.

Does anyone know the problem?