If the 'ol machine is dying then its time to train a new pup.
They are cheap enough to build if you feel comfortable doing that.
If not then have a look at
www.microdirect.co.uk , select systems on the menu then cursor down to 'systems - md set builds'
The cheapest one is the omega build at £247 + VAT. It has enough bells & whistles to satisfy most people and needs just a monitor and an operating system to be a complete working system.
Use this as a base spec & price while checking out the local shops.
Don't spend too much - it takes money away from flying.