Is Uninstal of CIS 3.5 Firewal advisable before 3.10 Firewall + A.V. and HOW

My AV is ESET NOD32 which I will uninstall.
Comodo 3.5 is my Firewall and DEFENSE +

The above is now to be replaced by CIS 3.10.

I believe it is not possible to export from 3.5 and import to 3.10,
so I assume I should uninstall 3.5 and make a fresh start with 3.10.

I would appreciate confirmation upon the above, and also HOW to succeed if first it fails ! !

Windows Control Panel ADD/REMOVE lists Comodo as an item it can remove.
Is there a better way ?
If it fails what alternatives do I have ?
What residual bits of Comodo should I seek and destroy from files / folders / or registry before installing 3.10 ?

I am hoping for advice by Wednesday so that Thursday morning I can download anything useful, and then switch off the Internet whilst replacing all my security. If I encounter any unanticipated problems I cannot switch on the Internet till they are fixed - or until I walk with a flash drive to the local library and use a public computer.

I am using XP Home edition with SP3

My apologies for posting twice.
I have been happy with 3.5 and not visited for a long time, the forums I knew are now archived, and I initially chose to post in the forum with the most recent posting. I now realise my mistake, sorry.

Regards
Alan