If you are running Windows Vista then you are at risk of your computer starting to slow down and sometimes hang up for no discernible reason. It may also suddenly fail completely leaving you without a system.
Upgrading is quite straightforward provided that your computer is powerful enough for, or can be updated to accommodate Windows 7.
Most computers running Vista should be OK with 7, or may just need some extra RAM ('thinking') memory added.
For more details, contact Andy on 020 8 662 1124 or firstname.lastname@example.org