Do you have files downloading, when LW shuts down? Try the tips here: Reduce the drag caused by LW
To disable ultrapeer capabilities in new versions, tools > options > advanced > performance. You can also try disabling Mojito DHT & TLS capabilities, & OOB searching.

The Java version that you'll link to from that post is now Java 6 update 7. Remove whatever Java's currently installed (via Add/Remove Programs) before you install the new one.

A few people have had problems with later Java versions, if you find that the latest update makes no difference, try this older version. Again - download
the JRE offline installer & remove your current Java before you install this one.
Archive: Download Java 2 Platform Standard Edition (J2SE) 5.0 Update 11