Since I have my seed phrase memorized and since I'm using Electrum for cool storage, for security I deleted the program from my Windows computer thinking that I could easily recover my wallet with the seed phrase.
Deleting a hot wallet doesn't make it cold storage.
I want to remove any trace that Electrum was ever on my computer. Can somebody tell me how to do this please?
You're going to have to wipe and overwrite your entire hard drive, ideally more than once. But it's much better to create a proper cold wallet, and move your funds there.
It's funny that on this forum people assume that every question is from a newbie.
That's probably because you ask Newbie questions
I've had several cold wallets including the Ledger before the notorious data hack, a trezor before it was stolen out of my hotel room and 2 versions of the Bitfi, the latest kept my bitcoin safe but I had to sweep the coins into Electrum as the wallets bricked.
Your current setup is not a cold wallet, and even hardware wallets are not cold storage (unless you never connect them to an online computer).
To create a real cold wallet using Electrum, you'll need something like this:
Offline and running without hard drive storage:Get a Linux LIVE DVD. Use Knoppix or
Tails for instance, or any other distribution that comes with Electrum pre-installed.
Unplug your internet cable. Close the curtains. Reboot your computer and start up from that DVD. Don't enter any wireless connection password. Keep it offline.
Start Electrum.
Then create a new wallet.
with memorization I can travel world-wide without customs asking me what is this weird little electronic device in my pocket or this note with 12 words on it.
Most people would instantly argue against memorizing the seed phrase, but this is a good scenario in which it can be useful.