Hello Mister_E

Many thanks for you reply....I lost much hair over this problem, but it is FIXED!

I'm so stupid...

Ok here goes...after getting a BIG BIG hammer ready for my computer...I try one more thing.

My wall plug (errr....americans call it wall wart?) you know what I am talking about, - so it was a switchmode 2A 12V. I put it on my scope and it was really noisy, the crystal was also drifiting quite a bit.
Soo.......I replaced the plug pack with a nice linear 500mA 12V and replaced the crystal with a nice stable 4Mhz and then viola...it works...ICD on serial port and MicroCode is super happy and back to 2m Serial Cable!

Hmmm...I had some 'other' hair loosing problems on my board before. Somehow I think it was caused by the switchmode supply. No more switchmode for me...:-)

I am surprised the PIC still runs really well, even with a switchmode, but looks like other stuff don't like it.