Sure. I'm assuming you're talking about files at that stored locally (on your own hard drive) and that you're using some version of Windows.
All you need to do is load up Windows Explorer, change directories until you're viewing the folders you need to change the read-only flags on and press CTRL-A to highlight everything in the directory. Once that's done, right-click on any one of the selected folders, select Properties and make sure the "Read-only" flag under Attributes is cleared. Press OK or Apply, and mission complete.