Problem after uninstall to downgrade

[t68]

Since my payment method module only supports VM up to 2.0.10 I tried to downgrade from 2.0.20b but that really messed everything up.
First I uninstalled 2.0.20b
Then I installed the 2.0.10 zip and after installation I  got some blue lines with info and one red with "error installing component".

When I try to open VM i get:
"
404 - An error has occurred.
Component not found
Return to Control Panel"

Also: the virtuemart icon in component menu disappeared.

I then uninstalled  2.0.10 and reinstalled 2.0.20b but get the same problem and error message.

Tried to drop all vm-tables and reinstall but it doesnt help.

Really need som help here!

Joomla version is 2.5.9

[jenkinhill]

No backup made? Do you not use Akeeba?

As you uninstalled and dropped the tables (so you really removed products etc)  the best way to go may be to start again with a new Joomla installation.  Due to security concerns I would not use a version as old as 2.0.10. Better to update the payment plugin to work with current versions - and VM2.1 is not that far away.

[t68]

Thank´s for a quick answer jenkinhill!

Since we´re still in test mode it was not a big deal uninstalling and dropping tables. Just a couple of testproducts in it.
But anyhoo, after a read up here: http://docs.virtuemart.net/tutorials/30-installation-migration-upgrade-vm-2/98-possible-virtuemart-installation-problems.html

I managed to clean up better after uninstall and successfully got 2.0.1 working.

And yes, I´m aware of problems running an old version, but I need to use this specific payment service here in Sweden (Payson) and unfortunately their module only supports VM up to 2.0.1. Been in touch with their support and they are stating that they are working on an update. Not sure how soon though.

And unfortunately I´m by far to bad at coding to try to manually update their modules.

But If any kind developer would like to have a peek at their module and see if it might just be some minor fixing to bring it up to par with the latest VM, it would be great. The module is downloadable at:
https://www.payson.se/integration/moduler/virtuemart