I wonder what "basic task" you're talking about ?
If it's normal tasks like many other people: music, mail, web browsing, video, IM, you will find no different with windows. I'm using Thunderbird, Chrome, VLC, Pidgin, Banshee and all of them work almost the same on 2 system.
When it comes to flash, in my opinion Flash in Ubuntu (using 64bit lab flash) is sucks, but when I switch to Windows at work, I found that Flash in Windows sucks too. Flash in Ubuntu works just fine, Chrome have flash and PDF viewer embed
Find software ? Is it your joke ? Any Linux distro has Software centre or some thing like that, it's even better in Ubuntu with theirs, install software with
I don't want to start a flamewar about Linux vs Windows, but your experience with Linux is too old, grab a modern Linux distro and change your mind.