Yeah, you're doing the right thing with Guiminer by having "-f 60" on the end. I do that on my Win7 machine and can watch videos and play games with no problems while mining (although at a 30% reduced hash rate).
For Litecoin mining on Windows, use ScryptMiner and take the threads down to less that the number of cores on your CPU. On my Win7 box, I can't run Guiminer for BTC and also run ScryptMiner for LTC unless the thread count = 1, and that's not worth it for me. If I try a higher thread count, my heat alarm on the CPU goes off.
You can build a Linux box (I use Xubuntu) just for mining fairly inexpensively, especially since you can use a USB drive in place of a HD.
On some algo,s (although at a 30% reduced hash rate). on my-gro it will go up it buy 3000% with high anuff dif my old con-fig -u worker.1 -p d=300 -f 1000 and i used d=1000 -f 300 / if i usd -m for it i will put p d=1000 -m 0.003.
each alog has dif programing ,and pool program also , like two pools same algo same coin and one will boot you the next will mine it. One will mine you at 20 mh/s the nest will put you at 60 mh/s ( they only use %10 of your gpu to mine and pool operators gov,n the diff of the coin not the blockchain the devs and pool operators do it on purpose ). with my mod i mine at 1th/s and not 60 mh/s for . i have 10 1080 ti,s and pools if i let set diff make me $6.00 a day with my mod i get $30 to $1000 a day ....( do not use in less you like mess up it takes alot of bad share to find the correct speed ) ps Uncle Scrooge i am sorry but i did make 40 people alot of btc intill you killed -f usage and now they do not mine with you ... and thank you for letting me find the 900 + shield blocks on my-gro , you get a gpu coin and i will mine for you ,but you keep the pool for asic only and that is wrong .