Ms Davis, under no circumstances do you want to anchor Pergo; if it's not allowed to float it will buckle and can separate, as the floor is designed to expand and contract.
One option to solve your problem would be to shim the subflooring from underneath. You will need to locate the low spots pretty accurately by measuring from fixed points, or "landmarks" like heating registers, etc which can also be located in some way from underneath the floor in the basement or crawlspace.(I HOPE this is not over concrete) This can even be done in some cases as simply as one person above tapping on the low area while one below locates the tapping. Then the subfloor can be eased slightly apart from the joist with a prybar until you have enough space to slide in shim material. Be careful to make the changes GRADUALLY (since you do not want to go too far and have nails sticking up), and double check how this feels from above before finally locking things back down by using construction adhesive in a caulking gun applied into any voids between shims, and down the edge of the joist and subfloor where you've moved the two.
You may also find that some low areas are actually between joists. In this case, install cross-blocking between the joists to stabilize the subfloor.