i cant put it on a ledger as diff algo , not bip39 on electrum it seems ...
Right. If your seed phrase has been generated by electrum, it's not BIP39.
any suggestion ? or do i have to go through downloading electrum (if so will buy new computer ) ? will the old seed still be compatible or do i need to pull a old electrum version
There is no need to go for an old version of electrum. You can use a new version of electrum. It's compatible with your seed phrase.
If you worry about security of your computer, you should buy a new one or format your hard drive and reinstall your operating system.
It may worth mentioning that you don't have to import your seed phrase into an online device. Electrum allow you to sign transactions offline.