Hello,
I can confirm this issue!
exactly the same as described above.
I use a Lenovo x201 with an i7 and indows 7x64 as well...
lets hope someone can find a solution...
UPDATE:
It just happened again, although this time i did not even upload anything...
The USB connection with the UNO was established and the sketch editor was open.. and then everything froze....
Please someone help, this is so annoying it kept me from playing with the Arduino for a whole year.....