Leaking vinyl windows

[math-ya]

The previous owner put these 2 windows in my attic. When the window sits closed in the vinyl frame- it isn't making a good enough seal. Water fills up the bottom of the frame, and eventually spills over into the house. these windows dont have weep holes- so I was just thinking about drilling some where the factory should have. Is this okay? I don't know how else to fix them without caulking them shut.

[Greg]

How do they open? 

I think weep holes are a good idea, but you may be seeing the result of too much moisture in the attic air hitting cold glass (condensation) and it has nowhere to go, not uncommon.  If you're sure the moisture is coming from the outside, then you can add some head flashing to direct water coming down the wall above the window to the outside so that it can't run into the top of the window. 

If you drill weep holes on the outside that's one thing but I'd be wary of drill any in-frame holes inside or in the window jamb unless you're certain what the extrusion looks like under the skin.  Maybe you can contact the manufacturer for advice.

[paddedhat]

Just for your own knowledge, you might want to take a framing square and check the sash and the frame to see if they are square. I have received windows, straight from the factory, that were too defective to install, as they were built out of square. I have also seen, and torn out, others installed by "carpenters" that probably lacked the skill set to pick up garbage in a job site, and sure as hell didn't know how to install anything plumb, level and square.

[math-ya]

They're regular sliders that open up and down. The water is def from the rain cuz when it sideways rains- the water just pours in the house, and weather stripping above wouldn't help cuz the water accumulates on the window itself (sideways rain is my problem)
Anyways I drilled the weep holes today, tested them and about a million dead lady bugs came out with the water ha.  Plus I got some intense sideways rain an hour ago. And I'm bone dry inside!