Okay, so a month or so back I reformatted my laptop's hard drive and reinstalled Windows XP, got all my drivers back and started using it as normal. However, occasionally (usually when I'm installing something, although sometimes it happens when I have my external hard drive connected as well) the laptop will start playing up, anything that was working would either start glitching out, give an error message or just randomly close, if I tried to open Task manager it would give me a "0xc000012d" error, the text in the Start button would disappear, my user name at the top of the start menu would also disappear, if I was in a folder and put my mouse over one of the little side bar menu things it would turn the same colour as the side bar.
This issue is making it almost impossible to use my laptop how I want it, since my desktop broke the other day I need this to function in its stead, just the basics though, a few games, iTunes (one of the installers that causes this error), stuff like that. However I can't install half the things I need, for instance the dotnet framework, as they all cause this error.
I've never heard of anything like this and anytime I try to Google it I find nothing that helps, any form of help would be very very much appreciated.
My laptop is an Acer Aspire One (model number ZG5) with a 1.60 GHz processor and 0.98 gig of RAM.