Random characters, computer won't boot

Hello. I have an HP computer running Xp Home that recently had the following message and wouldn't boot:

Windows could not start because of an error in the software.
Please report this problem as :
load needed dlls for kernel.
Please contact your support person to report this problem

I ran HP Recovery which resolved that error... but now I have another problem. During the recovery process there were several .DLL files that it said couldn't be recovered. Now when I boot I get the HP startup screen, then it goes to a black screen with about 10 random characters and figures which aren't even on the keybord, in the top left corner of the screen. It doesn't boot past this. However, if I press F10 during startup (which should be System Recovery) it doesn't give me the garbled letters and it boots normally. Has anyone come across something like this before? Thanks!