A virus on my laptop has corrupted Windows XP and is now deleted. It has however made it impossible to access the "Install Windows XP" setup option when I put the Windows XP into the disc drive (setup.exe will not run). Am I able to install Windows XP from the DOS screen options? Should I reboot and then try? Many thanks.

There are a couple of options that may be available to you. You could try setting the boot priority in your setup when the computer is starting up to CD/DVD drive and trying again. (usually I think it's the del or f12 key at startup) Or you could download and run a disk wipe utility. If you have suffered from a serious virus then this might be the best course of action, since just reinstalling windows may or may not fix the problem. Darik's Boot And Nuke | Hard Drive Disk Wipe and Data Clearing this link might help if you choose that route. Re-installing an operating system is always a pain, good luck.