I have inherited a computer which at the moment is running XP home is it possible for me to format the hard drive and install XP Professional? At the moment the pc wont even statup and load to the windows page
Yep you can format your hard drive, now i format the drive using the windows XP CD when it boots to CD, other and easy way is if you have a "FAT32" File system on your hard drive just insert a floppy with a Windows 98 StartUp and when it loads and you see the A:, Type "A:Format C: /s" "/s" is for system if you don't got memory available take it out and try again without that, it should format it just like new hard disk, use www.bootdisk.com to make a Windows 98 SE Startup Disk
You don't give much information but usually the answer is yes. Assuming that the hard drive isn't actually broken (you don't say why the PC won't boot), you just need a copy of XP. Alternetively the PC may already contain a copy of XP which you can use to reformat and reinstall. In thois case, when you start the PC, before Windows starts the BIOS will give a message like "Press Fnn to recover."