Hey I really need help on my dell laptop inspiron 2650
When I go to boot up a blue screen appears that says something like bad image checksum
And that is as far as the computer will go .

Sounds like your install of windoze has gone bad for some reason.
It will be worth trying a repair install.
Here's (http://www.microsoft.com/windowsxp/using/helpandsupport/learnmore/tips/doug92.mspx) the official Micro$oft way of doing a repair install,
And Here's (http://www.geekstogo.com/forum/index.php?showtopic=138) one with screen shots.

Basically this installs windows over the top of your current setup.
So you don't loose any information you already have.