You've got 2 problems now and so you will need to solve one before going on to the other.
You need to first be able to boot up your laptop and that means you will have to at least restore your command.com.
You will need to get a Win95 boot diskette from someone and boot your laptop from it and hold down the F8 key (I think that works on Win95) and let it boot to the command line.
Then copy command.com from the diskette to your hard drive and then see if your laptop will boot up. If it won't, then try booting from the diskette again and this time do a sys to your hard drive. This means logging to your floppy (keyin a:). Then while you are on the floppy type in sys c:
Now try to reboot your laptop. If you can reboot then we can go to the next step.
I might add that even if you can get the laptop to reboot there may be difficulty in upgrading to Win98. Compaq I believe has their own version of both Win95 and Win98 for their laptops and so you might not be able to use a standard Win98 CD or set of diskettes to do an upgrade.
But first let's see if you can get your laptop to reboot under Win95. In the meantime I will try to do some research about the Compaq Win98 upgrade issue.