i know my computer sucks but...

ok so i have a secound generation ibook and ive only had it for about a year and now a days it doesnt run applications right.
i love downloading applications from macupdate.com and now none of the programs work and i dont know what to do
help would be most appriciated

When you say it doesn't run applications right, can you give some more detail? Are you saying that the downloaded files won't open, or that other applciations won't work?

oh sorry i forgot to tell you yeah so when i open programs the icon bounces in the dock and then just disapears and it just doesnt open

Have you tried to repair your Hard Drive lately? You should also back-up any programs and files at this point and prepare for a reinstall of the OS.
First, verify how much disk space you have left?

Second, follow these instructions: http://docs.info.apple.com/article.html?artnum=106214

You will need your install CD/DVDs..

thanks alot you guys are awesome!!!