HTC Desire Z - Forever Freezing / Rebooting

[MinalMoe]

For the 4th time this year, my HTC Desire Z has gone back to HTC to be repaired without any final joy. In brief there are 3 main problems.

1. HTC Sense reloads most times after exiting an App.

2. The phone freezes requiring battery removal to restart.

3. The reboots itself.

Finally one of the primary colours for the screen started to go, so that white went to pale green and other colours lost their correct hue.

My warrantee runs out in 2 weeks, so what do I tell HTC to do?

Thanks