My computer will not boot up!

Hello all,
Please help. I was running Me but my computer was crashing all the time so I uninstalled Me but got some error regarding a file during uninstall. Now my computer will not boot up without a boot up disk. I tried installing Windows 98 but got a message that I already have windows software and that I must run the Windows 98 Upgrade. When I try to run the Windows 98 Upgrade I get an error that says “Not ready reading drive z”
What can I do?
Thanks,
Tim Tirendi
timt@writeme.com
215-439-2733